DESCRIPTION (Applicant's Description) The incidence of ductal carcinoma in situ of the breast (DCIS) has increased dramatically during the past decade largely due to the concurrent rise in the use of screening mammography. Since mastectomy remains the most common surgical treatment for DCIS patients, there is concern among clinicians and advocacy groups that many women with DCIS are being "over-treated" with the receipt of mastectomy. At the present time, no population-based studies have investigated whether the determinants of surgical treatment choice and satisfaction with choice differ for women with DCIS versus those with invasive disease. Thus, we propose to conduct an interdisciplinary pilot study of the determinants of surgical treatment choice across stages of disease using a population-based and racially/socioeconomically diverse sample of patients. We aim to develop and pilot test a mailed survey instrument in a sample of 280 recently diagnosed women (140 patients with DCIS and 140 patients with invasive disease) gathered prospectively as they are reported to the Detroit-area SEER registry. We anticipate a 70% response rate, which will result in approximately 200 respondents. In addition, we aim to use our experience and preliminary data from this pilot study to refine and set a hypotheses about the relationship of socioeconomic, psychological and clinical factors (including stage of disease) to surgical treatment choice and subsequent satisfaction with that choice. Finally, we will evaluate the study methodology to assess the feasibility of using self- administered mailed surveys to investigate breast cancer treatment decision-making, and to articulate the strengths, limitations and costs of this approach. The results of this study will serve as the foundation for a larger population-based study of factors associated with surgical treatment choice and satisfaction among breast cancer patients with DCIS versus invasive disease. Increasing knowledge in this area is likely to increase patient satisfaction with treatment decisions, improve patient adherence to treatment plans, and thus decrease negative sequelae costs (both economic and psychosocial) in the recovery process.